Apparatus for grinding material in a more or less viscous condition



June 2 7, 1939. A. soNsTl-IAGEN APPARATUS FOR GRINDING MATERIAL IN MORE OR LESS VISCOUS CONDITION Filed June 27, 1932 f-ff l. .Tl

I lllllltml I 4r Patented June 27, y1939 UNITED STAT APPARATUS YFOR oanNmNGfV MATERIAL v1N A MORE OR. Less viscous CONDITION VAsbjorn Sonsthagemr'London; lfngland Application June 27, 1932, Serial No. 619,539 In GreatBritan July 11, 1931 6l Claims.

viscous condition, and it refers to mills 'of the kind in which the material, in place of being acted `upon by tWo discs or rollers, is acted upon by a moving body, a disc or rollers for example, with which is associated a stationary member which may be a 'bar or a group of bars, beneath which the material passes whilst acted upon by the moving body.

Alternatively, the bar or group of bars constitute the moving body, the stationary body being formed by the disc or roller or the interior surface of a cylinder, the inner surface of the wall of a pan or container, with which the said bar or bars cooperate.

. The present invention has for its object certain improvements in mills of this type designed to increase their eiciency.

Duets or feed channels for materials are already in use and have longA been known for supplying material to the activemember of so called bar mills. Apart from their Vaction as serving tolead the material to a predetermined point, however, their effect upon the performance of the mill has vbeen a purely negative one.

According to this invention, there is provided a compression chamber which may conveniently comprise a channel or duct of gradually diminishing width, one side or wall of said channel or duct being constituted by the disc or other rotating or fixed body, the narrower end of the chamber being the exit end. The purpose of the duct is to' cause the material tobe supplied to the point of grinding or crushing under a considerable degree of pressure whereby not only is the action of the mill improved, but as compared with known mills, a

' considerably greater output per unit of timeis face of the disc or other moving body andthe other by a fixed body. The material is fed to the chamber in any suitable manner.

I have found that the angle of the Y,fixed Wall of the duct with respect to the moving surface is an important factor in securing the most effective y performancek of the mill, as also the height of the (Cl. 83-22l said wall. Thus,.for example, with'a material of a heavy viscosity the wallV could be inclined at an angle of with respect to the surface of the A, disc; with a material of lesser viscosity the best results will be securedl with an angle of 5, the,- disc rotating atthe same speed in both cases. The angle of the fixed wall is also dependent upon the clinging property of the material, the greater this the larger would be the angle of the said wall.

Instead of varying the angle of the fixed wall of. 10 the chamber, the same results may to a very large extent be secured by varying the height of the wall. j

In order that the invention may be the better understood, drawings are appended, in which: ,15

" Fig. l is a side view of a disc mill having a bar according to this invention. Fig. 2 is a view of the face ofthe bar.

Fig.'3 is a plan.V j

Figs. 4 to 'lare views showing a modified form.

of the invention; v

Fig; 8 is an end view showing the application of the invention to a preferred form of grinding bar.

9 is'aper'spective view showing a modification. Referring to the accompanying drawings, Figs.

l to 3, a indicates a metal body having a tapering channel or recess b running longitudinally thereof, said channel being designed to receive a block or mass of suitable material B, Fig. 1, granite for.; example, which'may be` secured therein by means Vof screws -passing through holesc tapped to receive them and formed in theY bottom of the aforesaid channel or recess b. I

Adjustment'of the distance between the face of Y,the block and the active surface ofthe bodyG- which need not of vnecessity have a rough or abrading surface, but, as in practice, may have a smooth highly polished surface, may be effected by means of screws passing through the back of the channel, tapped 4holes being provided vat e for their passage. i,

Projecting upwardsA from the front of the body ais a plate or flange f vrunning longitudinally of said vbody and having an'inclined surface g formed thereon, which surface, together with the surface of the abrasive body G, forms a pressure chamber of V shaped cross-sectional outline, the lower end of which'is-located closely adjacent the upper edge of the body B. I

The plate f may be so mounted as/to permit of angular adjustment', or provision may be made for theiapplication to plate f of other plates,.,the inner face .of whichy is inclined at a differentanglefrom that ofnthesaidjplate-f. g, i ,L 55

Studs or projections 7' are provided upon .the

back of the plate h and slots lc are provided upon the plate f to receive said studs whereby the plate h is held against longitudinal movement.

'Ihe construction of the plate f as a separate part capable of attachment to the metal body a presents the advantage that plates of Vdifferent inclination may be substituted with a-minimum expenditure of time and labour.

It must be understood that the plate must be .very rigidly and strongly mounted as the pressure isvery great at, and adjacent, the discharge point and only a comparatively minute displacementof the platev is sufficient to cause a considerable reduction in the efficiency of the mill. For instance, a displacement of .002 with material having a small clinging characteristic will be sufficient to influence the pressure to a very large extent.

In practice, it has been found possible to readily secure so V,high a degree of pressure at the .bottom of the chamber, that the material will enter the grinding gap under a pressure of 500 lbs. per square inch or .even more. Without such pressure at the bottom of the chamber it is .found that many materials .would simply be scraped olf and would not enter the grinding gap at all. Itis, therefore, necessary that the design of the chamber, that is to say, the angle and/or. depth. of its inclined wall thereof, be so selected that the desired result is obtained. A certain portion ofthe inlet side, when the materialv isunder compression, that is to say, at the .entrancetd` or between the grinding surface, is

referred to as the nip.

The chamber, as just described, may be supported by the stationary member or bar, or it lmay be associated with the hopper carrying the ".material in bulk, or, itmay. be supported from any other convenient part of 'theapparatus In all cases, however, provision may be made whereby vthe wall of the chamber may be adjusted towards and away from the surface of the rotary grinding body.

If desired, also, provision may be made wherei .y byA the depth of the chamber may be varied, for

example, by `increasing the height of the wall thereof by means of plates such as m, Ashown in interrupted lines in Fig. 9.

If desired, provision may be made for preventing Aor reducing the circulation of the material within the chamber, for which purpose the said chamber may be divided into a number of compartments by means of vertically arranged partitions o extending from the rear wall of the `chamberrto the, open side, as shown in interrupted lines in Fig. 9.

Any other suitable provision may, however, be made whereby circulation within the chamber is avoided.

.The presentinvention may also be employed in conjunctionwith grinding or crushing elements' having a number of effective surfaces,

some or all of which are disposed-at varying distances from the surface with which they cooperate.

In cases where the moving body is in the form of a roller, the foregoing remarks as to the angle and height of the Wall of the chamber will also apply. In this case, however, the inner surface of the wall is appropriately curved in order to secure the desired result.

In order to increase the effect of the chamber, the effective surface of the plate f may be roughened in any suitable manner, as for example, by leaving upc-n it the marks produced by the tool when planing it, for which purpose the tool would be given a coarse feed leaving ridges running longitudinally of the plate f. By this means the material may, so to speak, be gripped in the chamber.

The great pressure obtained by means of a chamber such as described could advantageously be employed for the handling of materials, which under the influence of heat and pressure can be brought from a powdered condition into a more or. less viscid condition. As an example of such a material, chocolate may be given, which, being ground on an ordinary roller-mill--as a half product under certain conditions is in the form of a dry powder which it is desirable to bring to a more or less viscid condition to facilitate the next step in the process.

Although I am not aware that it has hitherto.

been proposed to heatmills of the kind referred to for the purpose of securing results such as above outlined, it is evident that they can easily be either heated or cooled-as the case may be -`to obtain the advantages of the duct when handling more difficult materials.

The chamber would, under all circumstances, perform its fundamental function of creatingv the high pressure and it is evident that the very moving of material through the gap referred to in the foregoing description would always involve a rubbing and grinding action.

As previously stated, the invention may be employed in conjunction with a particular form of grinding or crushing element and in Fig. 8 there is illustrated one form of crushing bar such as that before referred to.

In Fig. 8 the body-a serves to retain a number of comparatively thin plates w, the inner ends of which `are disposed upon a line inclined with respect tothe surface of the disc G, their proper adjustment to the desired angle being effected by means of the backing plate :v adjustable by meansv of the screws passing through the tapped holes e, said plates being clamped in the body a by means of screws tapped into the holes c. By varying the outline of the surface o-f plate any desired setting may be imparted to the plates w, said plate a: moreover permitting ready adjustment of said plates w to compensate for Wear. The plate moreover will prevent any backward movement of the plates w.

I claim:

l. In a grinding mill for viscous material a moving body, a grinding member having a nip thereon and co-operating therewith, an extension upon said grinding member, a surface upon said extension inclined with respect to the surface of the moving body, said surface upon said extension together with the surface of the moving body forming a compression chamber of wedge-like cross-sectional outline, theV apex of which enters the nip v'for the material, means for vvaryingfthe height of the extension whereby the material enters the nip under considerable pressure.

2. In a grinding mill for viscous material, a moving body, a grinding member having a nip thereon `co-operating therewith, an extension upon said grinding member, a surface upon said extension inclined with respect to the surface of the moving body, said surface upon said extension together with the surface of the moving body forming a compression chamber of Wedgelike cross-sectional outline, the apex of which enters the nip for the material and whereby the material enters the nip under considerable pressure andmeans for varying the angle of the inclined surface of the extension, comprising a plate, an inclined surface upon said plate, and means for securing said plate to the effective surface of the extension.

3. In a grinding mill for viscous material, a moving body, a grinding member having a nip thereon comprising a number of elements having their active faces set at different distances from the moving body, a channel-shaped member, means for securing said elements in said lchannelshaped member, a projection upon the upper surface of said channel-shaped member, a surface upon said projection inclined with respect to the surface together with the surface of the moving body forming a compression chamber of wedge-like cross-sectional outline, the apex of which enters the nip for the material and whereby the material enters the nip under considerable pressure.

4. In a grinding mill for viscous material, a moving body, a grinding member having a nip thereon co-operating therewith, a channel-shaped member, means for securing said grinding member on said channel-shaped member, a projection upon the upper surface of said channelshaped member, a surface upon said projection inclined with respect to the surface of the moving body, a plate adapted to be applied to the inner face of the extension, the outer surface of said plate being inclined with respect to the surface of the moving body, said surface together With the surface of the moving body forming a compression chamber of wedge-like cross-sectional outline, the apex of which enters the nip for the material and whereby the material enters the nip under considerable pressure.

5. In a grinding mill for viscous material, a moving body, a channel-shaped member, plural members disposed in the channel of the rst member and having active faces positioned at different distances from the moving body, said members forming a nip, means seeming said plural members in the channel, said first member having thereon a surface which is inclined with respect to the surface of said body, said surfaces forming a chamber above the nip for receiving material to be ground. 6. In a grinding mill of the type having a stationary grinding bar and a revoluble grinding element moving past said bar and wherewith said bar has linear contact; means to feed material between the bar and rotary member under a high degree of compression and including a channel member supporting the grinding bar and having an extension projecting upwardly above said bar and having a plane face confronting the rotary element at an acute dihedral angle thereto, said dihedral angle having its apical edge lowermost and being of sufficiently small angular dimensions to produce high compression of material passing downwardly between the confronting faces of the bar and rotating member.

ASBJ ORN SONSTHAGEIN. 

